Wearables for detection of AF – Apple Heart Study

Wearables for detection of AF – Apple Heart Study

The Apple Heart Study was an app based study using smartwatch to detect cardiac arrhythmias [1]. The preliminary findings of Apple Heart Study has been presented at the American College of Cardiology meeting 2019 at New Orleans. The study enrolled enrolled 419,297 participants over a period of just 8 months, indicating the power of social media in enrolling participants. The number comes to about 1 in 600 adults in the United States of America. Of these, 24, 626 were aged 65 years or more.

Primary objective of the study was to measure the number of participants with an irregular pulse using the wearable monitor Apple Watch (Apple Inc, Cupertino, CA).

Secondary objectives were:

  1. Check the concordance of irregular pulse notification from the Apple Watch using simultaneously recorded ambulatory ECG using a wireless patch.
  2. Assess the rate of initial contact with a health care provider within 3 months of notification of irregular pulse.

The study was conducted virtually using a smartphone app which performed the screening, consent and data collection. Study visits were with video chat through the app by telehealth study physicians. Ambulatory ECG patches were mailed to the participants.

The study was spearheaded by the researchers from Stanford University School of Medicine.

The Apple Heart Study preliminary findings

The preliminary findings have been published as a news item at the Stanford University website [2]. Key points noted were as follows:

  1. Only fifty two basis points of participants received irregular pulse notifications.
  2. The positive predictive value was 71% on comparison with a simultaneous electrocardiography patch recording.
  3. 84% of time participants who received an irregular pulse notification was found to be in atrial fibrillation at the time of notification.
  4. Only 34% who received irregular pulse notification and checked with an ECG patch a week later were found to have AF. This is due to the paroxysmal nature of AF.
  5. 57% of those who received irregular pulse notification contacted a health care provider.

Thanks to my twitter friends for providing live updates from ACC 19.


  1. Turakhia MP, Desai M, Hedlin H, Rajmane A, Talati N, Ferris T, Desai S, Nag D, Patel M, Kowey P, Rumsfeld JS, Russo AM, Hills MT, Granger CB, Mahaffey KW, Perez MV. Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study. Am Heart J. 2019 Jan;207:66-75.
  2. Apple Heart Study demonstrates ability of wearable technology to detect atrial fibrillation. Stanford researchers presented preliminary findings from a virtual study that enrolled more than 400,000 participants. Available at: http://med.stanford.edu/news/all-news/2019/03/apple-heart-study-demonstrates-ability-of-wearable-technology.html?linkId=64879148. Accessed on 17th March 2019.

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